This invention relates to integrated circuits, and more particularly, to charge pump circuitry for integrated circuits.
Charge pumps are widely used in integrated circuits to generate desired voltages. For example, charge pump circuits may be used to generate power supply voltages. Charge pumps contain multiple stages connected in series. Each stage has an associated capacitor and a switching element such as a diode. When the stages are driven by an oscillator, an output voltage is produced at the output of the charge pump. The charge pump can be turned off by disabling the oscillator.
It is often desirable to provide an integrated circuit with a robust charge pump. A charge pump that is too weak may experience difficulties when a large load current is demanded. If a charge pump is made strong enough, however, the charge pump will be able to satisfactorily operate under a wide variety of load conditions.
Care should be taken, however, to avoid creating problems with an overly strong charge pump. As an example, a strong charge pump may respond too quickly to input control signals. This may cause the output voltage of the charge pump to change so rapidly that circuitry that is being powered by the charge pump output voltage does not operate properly.
It would therefore be desirable to be able to provide improve charge pump circuitry for integrated circuits.